What Is Realism in International Relations?

By Linda C. Ashar, J.D.  |  11/10/2026

International relations refers to how sovereign nation-states interact across borders through diplomacy, politics, and economics. Realism in international relations involves a foundational, dominant international relations theory that seeks to explain a government’s conduct in international politics and interactions among nation-states.

At its core, international relations realism is a political philosophy based on the practical assumption that nations operate on the global stage without a single governing authority over them that is capable of consistently enforcing rules. The sovereign government is ultimately accountable only to itself and is responsible for its own security concerns in exercising its national power.

The absence of a global central governance over independent nation-states is a condition of anarchy. Anarchy in this sense does not mean chaos or confusion. Anarchy by this definition means that there is no central binding enforcement authority of one superior governing agency to which all political institutions must adhere.

As a result, nations rely on themselves to maintain their continuing existence and protect their own national interests. In the international relations realist’s tradition, the key to protecting a nation’s self-interest is prioritizing its power and self-preservation. Power matters because power means control, and control means safety and stability for a nation.

In the comfort of stability, governments may cooperate with each other with peaceful interaction. They benefit from commerce and peaceful co-existence enhanced through treaties, international cooperative organizations, and diplomatic relationships.

However, realism theory in international relations states that such peaceful affinity ultimately derives from those governments serving their own strategic national interests. If international agreements conflict with a country’s national security, sovereignty, or economic priorities, realism theory predicts that governments will place their national interests first.

Realist theory does not dispute that international law, ethics, or independent international institutions are components of the dynamics of international relations. Any of these factors might figure in the equation of power, dominance, advantage, stability, and international security.

Instead, the proponents of realism theory question how much ethically focused cooperative enterprises can expect to be effectively persuasive against conflicting powerful national interests. A government may support international rules that nations have agreed upon because those rules promote stability, trade, security, or other objectives.

However, a realist in international relations will argue that a nation’s commitment to these rules will pale, if not crumble entirely, in the face of more compelling contrary political, economic, or military threats. A nation’s primary concern is its power, defined in material terms such as superior military capacity and economic prominence.

Thousands of years of history attest to examples of the primacy of national self-interest, where peace treaties were broken or never honored, alliances were dissolved, and former allies became enemies. Political morality and moral laws were not necessarily a consideration.

For global business operations and negotiations in the international community, understanding the realist’s perspective is especially useful. Legal obligations, political interests, economic competition, cultural differences, and ethical expectations are all components of national self-interest deeply embedded in the fabric of international transactions and will inevitably complicate them. Realism theory in international relations cautions that it is necessary to understand context from a pragmatic perspective.

Classical Realism in International Relations

International realism’s roots hearken back to classical political thinkers like the Greek historian Thucydides and British philosopher and political theorist Thomas Hobbes. The modern version of classical realism in international relations emerged in the twentieth century after World War II.

As the Cold War moved into high gear, German-American political scientist Hans Morgenthau published Politics Among Nations: The Struggle for Power and Peace in 1948.

Morgenthau saw the machinations of international politics as a mirror of human behavior, governed by a need to dominate foreign affairs out of an atavistic drive for supremacy and self-preservation. Under this theory, humans manifest this drive in the context of managing nations’ conduct in a relentless pursuit of power to keep their nation in a superior position to other nations.  

According to Morgenthau’s classical view of political realism, humans are inherently egotistical and obsessed with a fear of either enslavement or total obliteration. Realistically, international society is therefore a hostile place from the perspective of international relations.

Classical realism relations and the human drive for dominant survival overshadow not only domestic politics but also world politics on a global scale. It is the singular moving force governing foreign policy decisions.

As international relations developed after the Second World War, Morgenthau refined his theory with six principles in 1954.

Principle 1: International Politics Is Governed By Objective Laws Rooted in Human Nature

Realism holds that politics, like society more broadly, is governed by objective laws grounded in human nature. Its aim in international relations is to develop rational political theory by evaluating political actions, their likely consequences, and reasonable alternatives.

Example: Two rival states may both seek greater security. However, each nation interprets the other’s defensive military buildup as a threat, producing a predictable cycle of mistrust and drive to ensure a dominant position.

Principle 2: National Interest Is Defined in Terms of Power

Political realism defines national interest in terms of power and as a framework for understanding international politics and distinguishing political facts from economic, cultural, or similar concerns. The focus on power illuminates the framework driving the nation’s foreign policy, rather than complicating the analysis with individual motives, ideology, or popular myths.

Example: A government may maintain an alliance with another nation. There may be disapproval of its partner’s domestic policies or position on human rights, but the alliance strengthens the government’s security and regional influence.

Principle 3: National Interest Is Dynamic

Although national interest is consistently defined through the status of power, its specific goals, content, and use are dependent on a nation’s actual political and cultural context in time. Power structure is variable with circumstances and demands of the times.

Example: A state may prioritize territorial defense during wartime, then shift toward building trade access, energy security, or technological leadership when conditions change.

Principle 4: Abstract Moral Principles Cannot Be Uniformly Applied to International Politics

Realism recognizes there are moral implications in political action but rejects the rigid application of universal moral rules. Decisions must be adapted to the specific circumstances of the time and with consideration regarding the likely consequences for a nation.

Example: A democratic nation’s leader may negotiate with an authoritarian government to prevent a wider war, judging that the likely consequences of refusing diplomacy would be worse.

Principle 5: A Nation’s Moral Aspirations Differ from Universal Moral Principles

Realism rejects equating a nation’s asserted moral aspirations with universal moral principles and the tendency to present a country’s national aim as an agenda furthering universal truth. By viewing that all nations pursue their interests in terms of power, realism supports impartial judgment and policies that recognize one nation’s interests likely differ from others.

Example: A government may describe its intervention in a situation to be morally necessary. However, other nations may view it as that government’s effort to expand its power and influence in the international arena.

Principle 6: Power Is Autonomous in International Politics

Realism theory regards power as the central force in international relations, independent of economic, legal, moral, cultural, or other factors considered subordinate or critical to security and control.

Example: The terms of a trade agreement may appear to be economically inefficient or morally imperfect. However, those terms may still be pursued by the principal actors because the agreement strengthens a strategically important alliance.

The classical realism theory of international relations advances the view that nations form alliances far more for convenience against a greater existing or anticipated threat, rather than for principles of altruism. The essential need for survival and control in the balance of power will always be paramount.

Structural Realism in International Relations

Thirty-one years after Morgenthau first published his book, American political scientist and educator Kenneth N. Waltz introduced neo-realism theory (also called structural realism) in his book, Theory of International Politics.

Waltz focused on the anarchic structure of the international system of global politics. The absence of a global central governing authority (i.e., anarchy) isolates nations in their bubbles of self-interest on a world stage of changing alliances, situations, and conditions. Waltz pointed out that no nation can fully trust any other nation in an anarchic structure.

Waltz shifted the analysis from looking at the motives of individual leaders to nations’ relative positions of power in the global universe in which nations operate. Pragmatically, coexisting on the international arena without guaranteed guardrails means that each nation is on its own, operating on a “principle of self-help” to protect their international security, governmental and economic stability, and national autonomy.

Power remains at the heart of the realist’s theory. British economics expert Dr. Kwok Tong Soo demonstrated this point in the context of free trade agreements. He noted that free trade prices are determined by a government’s bargaining power (typically linked to the size of the country’s economy), not by market forces.

Realism vs. Liberalism in International Relations

Whether one believes it is human instinct or anarchic nationalistic caution – or both – that define the dynamics of international relations, both realism theories regard self-assured survival as the driving force.

What that means for a government is that it will differ from other countries. Realism does not dispute the need to comprehend differences and find mutual ground in international relations. Power is not developed, exercised, or maintained in a vacuum.

A competing philosophy in international relations is liberalism, which argues that realism theory disregards evolving higher principles that are important considerations in international relations. International liberalism holds that nation-states will embrace and advance international cooperation with shared values and collaborative economic enterprise because such cooperation serves their interests for long-lasting stability.

Furthermore, liberalism contends that humans – and the governments they form and influence – are capable of rational, ethical thought and behavior. Those governments are capable of commitment to diplomacy and peaceful alignment beyond their own interests, rather than defaulting to quick antagonism or single-minded dominance.

Liberal internationalists accept the realist’s concept of anarchic global structure. However, they argue that the uncertainty in the state of anarchic separateness of governments is overcome by the higher value and stability derived from:

• Peaceful cooperation
• Economic interdependence
• Collaborative international enterprise

The North Atlantic Treaty Organization (NATO) and the European Union (EU) are considered examples of liberalism theory in practice. Their agreements are binding on their members and demonstrate mutual commitment to shared values, interests, and security, extending the focus beyond power to a full embrace of the member nations’ combined interests.

Liberalism philosophy promotes global governance to support human rights, environmental conservation of resources, and cross-border economic growth. Non-governmental organizations and international organizations such as the World Trade Organization® and the United Nations have contributed significant progress that supports liberalist philosophy.

In contrast to realism theory, liberalism places ethical norms and moral judgment at center stage in international relations. Essentially, liberalism theory asserts that human beings can recognize and develop peaceful engagement in international affairs with acceptance of universal moral principles as the ultimate recipe for each nation’s own survival.

Liberalism in international relations also views international cooperation, interdependence, shared ethical values, and economic trade as peaceful contributors that sustain a nation’s international security.

Human rights, the moral significance of actions, and global governance play crucial roles in liberal internationalism. Realism in international relations acknowledges these areas, but its focus is a pragmatic reflection of a nation’s interest defined by what it perceives as vital to maintain secure borders and its sustained existence. The focus on power minimizes the importance of individual rights and humanitarian concerns central to liberalism’s view of successful political action.

For the realist, the specter of armed conflict – and the power balance it constantly threatens – will always be uppermost in the international power politics engaged in an anarchic international environment. In contrast, liberalism emphasizes that collective responsibility can overcome the realist’s single-minded focus on power, to protect human life in vulnerable populations, address humanitarian crises, and find peaceful resolution.

The Master of Arts in International Relations and Global Security at AMU

For students who want to improve their knowledge of international relations and global security, American Military University part of American Public University System (“AMU”) offers an online Master of Arts in International Relations and Global Security. For this degree program, students can enroll in courses such as international relations theory, international political systems, and international organizations. Other courses include an introduction to global security and conflict analysis and resolution.

This master’s degree also has several concentrations so students can choose the courses that suit their professional goals:

• Comparative and security issues
• Conflict resolution
• International and transnational security issues
• Peacekeeping

Students with an interest in studying political systems in regard to international relations may want to investigate the comparative and security issues concentration, which offers a course in comparative political systems.

For more information, visit AMU’s homeland security degree program page.

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